a very small amount of capped brood
Absolutely nothing to do with the introduced queen, then, so irrelevant.
You have one of two likely scenarios.
Most likely there is a queen, less likely there are laying workers (if that were the case there would be a few cells with eggs or open brood).
Without some history detail, you are not helping yourself; or us (to be relatively certain of what is actually the true facts) and so offer anything more than suggest a test frame.
Our view is likely 90% plus correct, but, as yet still only guessing.
Here is that guess again: You already have a queen in the hive.
BTW, did your 'local bees supplies' supply you with your lost Buckfast queen by any chance?
RAB